A liquid crystal panel used in a liquid crystal display device such as a liquid crystal television, for example, does not emit light, and thus, it is necessary to provide a separate backlight device as an illumination device. This backlight device is provided on the rear side of the liquid crystal panel (a side opposite to the display surface), and includes a chassis that is open towards the liquid crystal panel, a light source housed in the chassis, and optical members (diffusion sheet and the like) that are disposed facing the light source and covering the open side of the chassis, the optical members being provided to efficiently emit light from the light source toward the liquid crystal panel. LEDs are sometimes used as the light source among the constituent members of the above-mentioned backlight device, for example, and in such a case, an LED substrate having the LEDs mounted thereon is stored in the chassis.
The disclosure of Patent Document 1 below is one example of the backlight device that uses LEDs as the light source.